CD25 depletion reduces virus-specific immune responses. (A) FACS analysis of CD4⁺ T cells following depletion of CD25⁺ T cells. (B) Production of cytokines by total or CD25-depleted CD4⁺ and CD8⁺ T cells following Gag-specific stimulation in vitro. Cells were obtained from lymph nodes or blood before the initiation of the study. (C) Schematic representation of the study design and numerical designation of the animals enrolled. *Mamu-A*01⁺ macaques.